How can I make a plane always look at camera?
I think I know what you're talking about (cause I'm a huge fan of these kind of oldschool 3d-imitating games :)). You may use a Damped Track constraint.


Select the plane, go to Constraints header, select a Damped Track constraint and set the Camera as a Target. Then select an axis you want a plane to lie on.


If you move the plane in any direction it'll always face the camera. Remember that you may also decrease the Influence of this constraint for different results.